1. Field of the Invention
The invention relates in general to a source driver output stage circuit, buffer circuit and voltage adjusting method thereof, and more particularly to a source driver output stage circuit with an AD-class output structure, buffer circuit and voltage adjusting method thereof.
2. Description of the Related Art
FIG. 1 is a block diagram of a conventional source driver output stage circuit. A conventional source driver output stage circuit 100 includes a high-voltage output buffer (Buffer_HV) 110, a low-voltage output buffer (Buffer_LV) 120 and a multiplexer 130. The high-voltage output buffer 110 and the low-voltage output buffer 120 are respectively coupled to high and low analog input voltages Vh and Vl, such as 12V and 0V, for adjusting output voltages Vo1 and Vo2 to have the same values as the voltages Vh and Vl in a charging/discharging way. Afterwards, a polarity-inversion operation is performed on the output voltages Vo1 and Vo2 for supplying an enough pixel current to the display panel 140.
However, the conventional buffers 110 and 120 are implemented by A-class amplifiers and have issues of high electricity consumption and inadequate power efficiency and driving power. In some cases, the buffers 110 and 120 may be implemented by AB-class amplifiers to improve power efficiency, which increases an area of the output stage circuit 100 instead. Moreover, no matter whether the A-class or AB-class output structure is used, there exists an issue of chip over-heating due to too high temperature.